British Interior Minister Sajid Javid has denounced social media networks’ inefficiency when it comes to blocking the circulation of extremist and violent videos on their channels following Friday’s mass shootings at mosques in New Zealand, which left 49 dead and at least 40 injured.

The Twitter handle @brentontarrant — now archived — shared pictures of guns a day before the attack featuring the names of others who had committed race or religion-based killings in white letters.

Other tweets from the same account talked about decreasing white fertility rates and linked to articles about right-wing extremists.

The Twitter profile had 63 tweets, 218 followers and was created last month.

A Facebook account with the name of Brenton Tarrant — also now archived — had posted YouTube videos featuring racist and anti-immigrant messages.

Footage of the shooting, allegedly filmed live by the gunman as the attack unfolded, was widely circulated on social media. The video was live streamed to the Facebook page of Brenton Tarrant using an app designed for extreme sports enthusiasts. Copies of the footage were still being widely shared online hours later.

Social media giants Facebook, Twitter, and YouTube (owned by Google) said they were working to take down content related to the attacks.

On Friday, Facebook tweeted that it had deleted the Facebook and Instagram accounts linked to the account and that it had removed the live-streamed footage.

A day later Mark Zuckerberg's company said it had removed 1.5 million videos globally of the shooting in the first 24 hours of the attack.

The company added it was also removing all edited versions that did not show any graphic content out of respect for the people affected by the attack and the concerns of local authorities.

A Twitter spokesman said the company was "deeply saddened" by the attacks.

"Twitter has rigorous processes and a dedicated team in place for managing exigent and emergency situations such as this," the company said in an emailed statement to Reuters. "We also cooperate with law enforcement to facilitate their investigations as required."

Similarly, YouTube said they were working “vigilantly to remove any violent footage”. But their response was widely criticised by politicians like Javid and Deputy Leader of the British Labour Party, Tom Watson, who called out the fact that live streams of the attacks were still viewable with "inappropriate" content warnings.

Chat platforms also a breeding ground of radical and extremist views

Minutes before the gunman opened fire in the first mosque, a user on the "Politically Incorrect" forum on 8chan — a chat platform with no restrictions on hate speech — wrote that he would carry out an attack "against the invaders" and that he would be live streaming it on Facebook. His post also included a link to a 74-page manifesto which spoke ill of minority communities and a link to the Facebook page where the attack was live-streamed.

But this is not a new phenomenon, other extreme right-wing sympathizers who carried out mass shootings in the name of an ideology, such as Dylan Roof and Anders Breivik, had also published their manifestos online before conducting an attack.